(boolean? #t)
(boolean? #f)
(boolean? 1)
(number? 42)
(number? 1/2)
(number? 3.14)
(number? 1+2i)
(number? 'symbol)
(integer? 42)
(integer? 1/2)
(rational? 1/2)
(rational? 42)
(real? 3.14)
(real? 42)
(complex? 1+2i)
(complex? 42)
(symbol? 'hello)
(symbol? 42)
(pair? (cons 1 2))
(pair? '())
(string? "world")
(string? 42)
(char? #\a)
(char? 42)
(procedure? +)
(procedure? 42)
